Based on usage it can refer to Cytogenetic which is the study of cells hereditary materials, Cytopathology means the study of cellular disease and the use of cellular changes for the diagnosis of disease as well as Cell biology means the study of (normal) cellular anatomy, function and chemistry.
Cell: A cell is the basic unit of life in which all organisms are made off. It is a membrane-bounded unit that contains the DNA hereditary machinery and cytoplasm. All organisms are cells or aggregates of cells.
1.1. Cell Theories/ Cell Doctrines
The cell theory, in its modern form, includes the following three principles
i. All organisms are composed of one or more cells.
ii. Life processes of metabolism and heredity occur within these cells this is due to the fact that the cell consists of hereditary materials
iii. Cells are the smallest living things, the basic units of organization of all organisms.
iv. Cells arise only by division of a previously existing cell. Although life likely evolved spontaneously in the environment of the early earth, biologists have concluded that no additional cells are originating spontaneously at present.
1.2. Challenges of The Cell Theories
i. It is true that cell is the basic unit of life but challenge comes from the virus which carries life processes although it is not a cell.
ii. It is true that all cells exists from the pre-existing ones but the challenges comes from what cell is the origin of the first cell
iii. It is true that cell has genetic materials which are transferred from one generation to another but the challenge comes from virus which is not the cell but it has hereditary materials
iv. It is true that living organisms composed by one cell or many cells but the challenge comes from the virus which has no cell.
1.3. Types of Cells
Basically there are two types of cells. These are classified according to the structure of the nucleus. These types of cells includes
i. Prokaryotic cells
ii. Eukaryotic cells
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